Assume BUCK has applied my commit to use set -e when running a
genrule(). This allows us to use ';' in all genrule commands and
trust the build will stop if any of the single statement terminates
with a non-zero exit status.
$SRCDIR is a cleaner reference to the sources of a genrule(),
fixing an ugly reference to the (supposedly hidden) __srcs directory.
Add a comment about the version generator, BUCK wants to make genrule
output fully cacheable, which requires rules to be idempotent.
Change-Id: I938450ed81675330e979d76721e0ba971d30d0e2
a0c9372baa